feat: add aggressive cows algorithm

[aartigawade2586]

Description of Change

Added an implementation of the Aggressive Cows problem using binary search
on the answer and a greedy feasibility check.

The solution:

• Sorts the stall positions.
• Uses binary search to find the maximum possible minimum distance.
• Uses a greedy approach to check whether all cows can be placed.
• Includes self-test cases using assert().

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes: Added search/aggressive_cows.cpp with a binary-search-based solution and self-tests.

[realstealthninja]

could you add some references as to where this problem originates from?